<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name=viewport content="width=device-width,initial-scale=1,user-scalable=no">
    <title>蒙版与禁止滚动</title>
    <style>
        .container{
            width:200px;
            height:2000px;
            background-color:blue;
        }
        .modal{
            width: 100%;
            position:fixed;
            top: 0;
            bottom: 0;
            left: 0;
            right: 0;
            z-index: 999;
            background-color: rgba(0,0,0,0.7);
            background-size: 100%;  
        }
        .p{
            font-size: 50px;
            color:red;
            text-align:center;
        }
    </style>
</head>
<body>
    <div class="container">
        <p>内容</p>
    </div>
    <!-- 蒙版 -->
    <div class="modal">
        <p class="p">按钮</p>
    </div>
</body>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>

<script>
$(function(){
    // 阻止蒙版后页面滑动
    if(/Android|webOS|iPhone|iPod|BlackBerry/i.test(navigator.userAgent)) {
    //移动端
        $(".modal").on('touchmove',function(e){
            e.stopPropagation();
            e.preventDefault();
            $('.p').click(function(){
                $(this).parent().hide();       
            })
        })
    } else {
        //PC端
        var flag=true;
        $('.p').click(function(){
            $(this).parent().hide();
            $('body').css({    "overflow":'visible'});
            flag=false;     
        })
        if(flag)
            $('body').css({"overflow":'hidden' });
    }
})
</script>
</html>
